National 5 Unit 3

6. Glucose made during photosynthesis is converted into this structural carbohydrate found in the cell wall.
10. An organism that eats both plant and animal material.
13. An isolation barrier caused by different mating rituals or signals.
14. A group of organisms that can interbreed to produce fertile offspring.
15. Chemicals added to soil to increase the nitrate content and improve crop yield.
16. An isolation barrier caused by different habitats or breeding seasons.
19. The total number of individuals of one species in an ecosystem.
21. Factors like light intensity or temperature that can slow down the rate of photosynthesis.
24. Competition between individuals of the same species for all the same resources.
27. The second stage of photosynthesis where carbon dioxide and hydrogen are joined to make sugar.
29. An organism that by its presence or absence shows you the environmental quality of an area.

1. A random change to genetic material which is the only source of new alleles.
2. The green pigment in chloroplasts that traps light energy.
3. An alternative method of pest control that uses a natural predator or parasite of the pest species.
4. Chemicals sprayed onto crops to kill organisms that reduce yield.
5. All the populations of different species that live together in an ecosystem.
7. A consumer that eats only plant material.
8. A diagram used to represent the energy or organisms at each level of a food chain.
9. The first stage of speciation where a population is split into sub-populations.
11. All the organisms living in a particular habitat and the non-living components with which they interact.
12. Competition that occurs between individuals of different species for a few of the same resources.
17. An inherited characteristic that makes an organism well suited to its environment.
18. All the non-living factors in an ecosystem
20. A different form of the same gene, often produced by a mutation.
22. Decomposers that use up a lot of oxygen in polluted areas.
23. The build-up of toxic substances in the bodies of organisms along a food chain.
25. A type of isolation barrier such as a mountain range or ocean.
26. The process by which two or more species are formed from a common ancestor.
28. The role that an organism plays within its community.